1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) field, more particularly, to a driver for rapidly adjusting current flowing through a light emitting diode (LED) series circuit of a LED backlight source to a constant current, an related LED backlight source using the driver and an LCD device using the LED backlight source.
2. Description of the Prior Art
As the progress of display technology, backlighting used in the LCD device has been developed. A cold cathode fluorescent lamp (CCFL) for use in a backlight source of a traditional LCD device presents disadvantages over poor color recovery, low lighting efficiency, high discharging voltage, poor discharging characteristic under low temperature and long time period to be heated to emit light with steady grey level. Nowadays, many LED backlight sources are developed.
The LED backlight source are disposed near the LCD panel in the LCD device, so that the LCD panel shows images by using light emitted by the LED backlight source. The LED backlight source includes an LED series circuit having multiple LEDs connected in serial. A specific driver is designed for supplying driving voltage to the LED series circuit. For prolonging lifetime of each LED, driving the LED series circuit with a constant current is required. However, the conventional driver needs a longer time period which the current flowing through the LED series circuit approaches to constant value, and causes higher power consumption, slower response time and worse operating efficiency.